This invention relates to joist bridging, and more particularly to bridging for installation between wood floor joists in floor constructions.
Use of bridging between joists in floor construction is important for maintaining the load-bearing capacity of the joists and for transferring loads substantially uniformly throughout the floor system. In this regard, it will be understood that, without bridging, joists may tend to become inclined off vertical on their supporting structure (e.g. walls or beams) resulting in decrease in their load-bearing capacity and development of an undesirable springiness in the floor and an undesirable tendency for the floor to squeak. For some years, however, there has been a tendency in home construction to omit bridging because its installation is labor intensive and therefore relatively expensive.
One type of conventional bridging comprises pieces of lumber approximately 1".times.3".times.16" installed in pairs with the two pieces of each pair side-by-side in an X-pattern between two adjacent joists, each piece being nailed (usually by means of two nails) at its upper and lower ends to the joists. Another type comprises steel pieces which are similarly arranged and nailed in place, or which are formed with an integral nailing means for nailing to the joist at the upper ends of the pieces. A third type comprises pieces of lumber such as pieces of 2".times.4" lumber or 2".times.10" lumber cut to the correct length to fit between joists with respect to the center-to-center joist spacing (this spacing typically being 16"). This third type is expensive not only because of the required cutting to length, but also because it requires installation with a minimum of two nails at each end, which generally require relatively considerable time and effort to drive. Also, the nailing in place of one piece of bridging tends undesirably to cause separation of the previously nailed-in place piece from the joist.
With regard to the first and second types of conventional bridging as above described, the top ends of the bridge pieces must be nailed first before the flooring is applied, on account of the hammer clearance needed, for nailing. The lower ends are nailed after the flooring has been installed. This is difficult and time consuming even in the case of a house with a basement, and may be impossible in the case of a house without a basement. Home construction is more difficult in the typical situation where the flooring is constructed of 4'.times.8' pieces of plywood and where, heretofore, the general practice when using the conventional first type of bridging above mentioned has been to nail the upper ends of the bridging pieces first, then individually aligning the joists to conform to the plywood pieces so that the edges of two adjoining pieces of plywood bear on top of a joist, and then nailing the lower ends of the bridging pieces. The problem here is that flooring proceeds over joists that are unstable due to the bridge pieces not yet having been nailed at their lower ends, creating a dangerous working environment and the potential for exacerbating an already dimensionally imprecise placement of the joists.